تقرير
Lattice dynamics and elastic properties of alpha-U at high-temperature and high-pressure by machine learning potential simulations
| العنوان: | Lattice dynamics and elastic properties of alpha-U at high-temperature and high-pressure by machine learning potential simulations |
|---|---|
| المؤلفون: | Wang, Hao, Pan, Xiao-Long, Wang, Yu-Feng, Chen, Xiang-Rong, Wang, Yi-Xian, Geng, Hua Y. |
| المصدر: | Journal of Nuclear Materials 572, 154029 (2022) |
| سنة النشر: | 2022 |
| المجموعة: | Condensed Matter Physics (Other) |
| مصطلحات موضوعية: | Condensed Matter - Materials Science, Condensed Matter - Strongly Correlated Electrons, Physics - Computational Physics |
| الوصف: | Studying the physical properties of materials under high pressure and temperature through experiments is difficult. Theoretical simulations can compensate for this deficiency. Currently, large-scale simulations using machine learning force fields are gaining popularity. As an important nuclear energy material, the evolution of the physical properties of uranium under extreme conditions is still unclear. Herein, we trained an accurate machine learning force field on alpha-U and predicted the lattice dynamics and elastic properties at high pressures and temperatures. The force field agrees well with the ab initio molecular dynamics (AIMD) and experimental results, and it exhibits higher accuracy than classical potentials. Based on the high-temperature lattice dynamics study, we first present the temperature-pressure range in which the Kohn anomalous behavior of the ${\Sigma}$4 optical mode exists. Phonon spectral function analysis showed that the phonon anharmonicity of alpha-U is very weak. We predict that the single-crystal elastic constants C44, C55, C66, polycrystalline modulus (E,G), and polycrystalline sound velocity ($C_L$,$C_S$) have strong heating-induced softening. All the elastic moduli exhibited compression-induced hardening behavior. The Poisson's ratio shows that it is difficult to compress alpha-U at high pressures and temperatures. Moreover, we observed that the material becomes substantially more anisotropic at high pressures and temperatures. The accurate predictions of alpha-U demonstrate the reliability of the method. This versatile method facilitates the study of other complex metallic materials. Comment: 21 pages, 9 figures, with Supplementary Material |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1016/j.jnucmat.2022.154029 |
| URL الوصول: | http://arxiv.org/abs/2210.01378 |
| رقم الأكسشن: | edsarx.2210.01378 |
| قاعدة البيانات: | arXiv |
كن أول من يترك تعليقا!